JP2002251784A - Optical disk substrate and optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain optical disks which permit simultaneously molding of dum my substrates and information substrates by using the same molding equipment relating to the optical disk substrates, rearranges and simplifies the layout of manufacturing equipment, attains the compatibility of the saving of a storage space with the temporary storage in a single plate state in a manufacturing process step and the protection of the disk in the superposing storage after sticking and do not hinder the work of printing the surfaces of the optical disks with labels. SOLUTION: Stack ribs 61 formed at the inner peripheral parts on the mirror finished surface sides of the optical disk substrates 81 used for the optical disks of a bonding type are formed to a projecting shape of an externally toothed gear shape repeating the patterns combined with projections of different shapes at prescribed periods and hollow grooves 65 formed in the inner peripheral parts by the pawls of the inner peripheral holders of a stamper on the information surfaces on the opposite side are formed to the hollow groove shape of the same shape inverting ruggedness from the ruggedness of the stack ribs in the same radial position as the stack ribs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an optical disk formed by bonding two or more optical disk substrates, an optical disk substrate, a molding die for an optical disk substrate, and a bonding apparatus for bonding an optical disk substrate. This prevents the optical disc substrates from being in contact with each other and damaging the signal surface or the like.

[0002]

2. Description of the Related Art Various types of optical disks, such as a CD system, an MO system, and a DVD system, are used as optical information recording media in a type suitable for each use, such as read-only, additional recording, and rewriting. The substrate used for such an optical disk is formed by injection molding or injection compression molding using a resin mainly composed of polycarbonate in terms of production efficiency and cost. In any of these optical disk substrate molding methods, a cavity is formed by closing a mold and filled with a molten material resin, and the molten resin is cooled and solidified in the mold until a temperature at which the resin can be taken out. Is formed into a predetermined substrate shape. In the above-mentioned cavity, a stamper in which information necessary for the optical disc is engraved as a pit row or a guide groove is set, and during the process of filling the above-described molten resin into the cavity and solidifying it, The information engraved on the stamper is transferred onto the optical disk substrate to be molded.

The stamper has a thickness of about 0.3 mm.
It is a donut-shaped plate with a hole in the center at a degree.
When the stamper is set in the mold, it is general that the outer peripheral portion is vacuum-sucked to the mirror surface of the mold and the edge of the center hole is mechanically fixed by the claw of the inner periphery of the stamper. Therefore, on the optical disk substrate formed as described above, the pit row and the guide groove engraved on the stamper are transferred, and the shape of the above-described stamper inner peripheral holding claw is formed in an annular shape on the inner peripheral portion of the optical disk substrate. It is formed as a concave groove. After the cooling step is completed, the optical disk substrate molded in the molding die is taken out by opening the die, and further cooled to a room temperature atmosphere before being transferred to the next step. For the delivery to the next process, there are a case where the optical disk substrates are successively delivered one by one, and a case where the optical disk substrates are once stocked in a storage jig and then put into the next process in a unit of a temporarily stored lot. Once the optical disc substrate is stocked in the storage jig and then put into the next process, the difference between the tact time of the next process and the tact time of the molding process is absorbed to optimize the tact time of the entire optical disc production line. It is to make it. The temporary storage of the optical disk substrate when the optical disk substrate is transferred between the processes as described above absorbs a tact time difference between the processes, such as a time during which equipment is stopped for setup and maintenance work. It is often adopted not only between the molding step and the next step but also between the optical disk manufacturing steps after the molding step using a molding die. The method of temporarily stocking the optical disc substrate between each process includes a method of stocking the optical disc substrates in a horizontal state with the optical disc substrates standing upright using a storage jig such as a stocker magazine, and a method of stacking poles. There is a method of stacking the optical disk substrates in the vertical direction while keeping the optical disk substrate in a horizontal state (in other words, a method of “flat-stacking” the disks) using the storage jig. In addition, a method of flat stacking optical disk substrates using a storage jig such as a stack pole is generally adopted because the installation area required for storage can be reduced. When storing the optical disk substrates in a flat stack as described above, due to the warp originally possessed by those optical disk substrates, or of the optical disk substrates themselves,
There is a problem that the optical disc substrates come into contact with each other due to the flexural deformation due to the own weight increased by the stacking and cause a scratch on the mirror surface or the information surface side of the optical disc substrate, thereby deteriorating the signal characteristics of the obtained optical disc.

In order to solve the above-mentioned problem,
When the optical disk substrates are stacked on the stack pole 1 and stored, a ring-shaped spacer 3 is inserted between the optical disk substrates 2 and 2 to store the optical disk substrates 2 and 2 during storage.
An operation is performed to secure a sufficient space (space) 4 between the optical disk substrates 2 and 2 so as to avoid surface contact with each other (see FIG. 1). We are trying to avoid deterioration. However, at the same time, the operation of inserting the spacer 3 between the optical disk substrates 2 and 2 when stacking the optical disk substrate 2 on the stack pole 1, and the operation of inserting the spacer 3 between the optical disk substrates 2 and 2 when removing the stacked optical disk substrate 2 from the stack pole 1. Since the operation of taking out the spacer 3 between the two needs to be performed at the same time, the operation of stacking and storing the optical disk substrate 2 and the operation of taking out the optical disk substrate 2 become complicated, and equipment such as a robot for performing these operations becomes expensive. To avoid the complexity of inserting the spacer 3 and removing the spacer 3, an annular projection called a stack rib 22 is provided on one surface (mainly a mirror surface) of the optical disk substrate 21 so as to eliminate the spacer. A method of providing the same has been proposed (see FIG. 2). By providing the stack ribs 22 in this manner, even when the optical disc substrate 21 is stacked on the stack pole 1 without inserting a spacer between the optical disc substrates 21 and 21, only the above-described protruding portion of the stack rib 22 is provided. , Stacked optical disk substrates 2
A gap 31 can be secured between the optical disk substrate 21 and the optical disk substrate 21.
Are prevented from contacting each other (see FIG. 3). At the same time, the operation of stacking and storing the optical disk substrates 21 and the operation of taking out the optical disk substrates 21 are also simplified, and equipment such as a robot for performing these operations requires only a simple and inexpensive mechanism. In addition, the stack rib 22 described above is
It is formed in a portion excluding an information recording area including a lead-in / out area of the optical disc and a clamping area area provided on an inner peripheral portion of the optical disc substrate. On the information recording surface side opposite to the mirror surface side where the stack rib 22 is formed, as described above, the inner peripheral portion of the stamper 71 is mechanically held and the stamper 71 is set on the mold mirror surface. An annular groove is formed by the claw 73 of the circumferential retainer 72 (see FIG. 8). If the annular groove and the stack rib are formed at the same radial position, when the disks are stacked, the irregularities of the two are combined, and it becomes impossible to secure a sufficient gap between the disks. For this reason, when both are formed at different radial positions or at the same radial position, the convex shape of the stack rib is made sufficiently large as compared with the annular concave portion.

As described above, the stack ribs 22 are formed on one surface of the optical disk substrate 21 so that the optical disk substrates can be temporarily stacked and stored as needed in the optical disk manufacturing process. After completion, the optical disks can be prevented from contacting each other when they are stacked and stored, and the operation of stacking and storing the optical disks described above and the operation of removing the optical disk from the stored state are easy. Can be However, it has become clear that the formation of the above-described stack ribs 22 causes a new problem. In other words, 1
There is a demand for a large capacity to increase the amount of information mounted on one disc and a miniaturization to reduce the size of one disc. One of those that can meet such a demand is a DVD disc. This means that the information recording capacity has been dramatically increased so that moving image information of 2 hours or more can be mounted on a disk having a diameter of 12 cm.

[0006] In order to respond to both the increase in the recording procedure and the demand for downsizing of the disk, it is essential to increase the density of information recorded on the optical disk at a high density. And what is required of the optical disk substrate for this high density,
In order to accurately transfer pits or guide grooves, which have become denser with the increase in density, onto a substrate, and to secure a tilt margin of a pickup of an optical disk device that reads information on an optical disk or writes on an optical disk. In some cases, the optical disk substrate is made thinner. For example, the thickness of the substrate of a DVD disk is half of that of a CD disk corresponding to the optical disk of the previous generation, which is half the thickness of the substrate.
6 mm. However, when the thickness of the optical disc substrate is reduced, the strength of the optical disc substrate itself is reduced, and the shape required for the optical disc cannot be maintained. For this reason, the DVD disk employs a structure in which a dummy substrate having the same thickness of 0.6 mm is bonded to an optical disk substrate on which information is mounted, thereby providing the required strength as a DVD disk.
The shape can be maintained.

[0007] As described above, an optical disk using an optical disk substrate thinned for large capacity and high density is
The configuration in which two (or more) optical disk substrates are bonded to each other ensures that the optical disk has the necessary strength and shape. However, the adoption of the new configuration of “bonding” simultaneously causes a new problem. The new problem is as follows due to the convex shape of the stack rib.

[0008] In the case of bonding substrates having protrusions which are stack ribs, if the protrusions are located inside the bonding, the protrusions interfere with each other and the bonding surface becomes flat, so that proper bonding cannot be performed. Therefore, stack rib 2
The lamination is performed with the surface on which No. 2 is formed outside, and as a result, the stacked ribs 22 are formed on both surfaces of the optical disc 40 after the lamination (see FIG. 4). When these are stacked and stored, the optical discs 21 and
Unnecessary voids 51 are formed between the two (see FIG. 5), which wastes the storage space. On the other hand, in order to eliminate the waste of the storage space, the stack is made such that the gap 51 formed between the optical disks 40, 40 is minimized and sufficiently large in a state where the optical disks after lamination are stacked. If the protruding height of the ribs 22 is set, the size of the gap between the optical disk substrates is insufficient when the optical disks are stacked in a single plate state before bonding, and the optical disk substrates come into contact with each other, causing optical defects.

The problem that the stack ribs 22 protrude from both sides of the bonded optical disk 40 is a problem that occurs when a label is displayed on the optical disk 40. A label on which a title or a picture designating information mounted on the optical disc 40 is designed is usually printed by screen printing on a surface opposite to a laser light incident surface for reading / writing information. When this is applied to the laminated optical disk 40, label printing is performed on the surface of the optical disk 40 on the side of the dummy substrate. However, the screen printing screen is damaged, and the number of disks that can be printed on one screen is reduced. Further, since the screen cannot properly contact the disk surface in the vicinity of the stack ribs, good printing cannot be performed. Therefore, there is a restriction that the label design cannot be designed to the vicinity of the stack ribs 22.

In order to solve the above-mentioned problem caused by the stack ribs 22 protruding toward the dummy substrate, the "laminated optical disk" of Japanese Utility Model Registration No. 30222434 discloses a flat optical disk having no stack ribs on the dummy substrate. Uses a substrate. In Japanese Unexamined Patent Publication No. 9-180251, “Disc substrate, molding die and optical disk”, stack ribs are protruded toward the bonding surface side of the dummy substrate to flatten the opposite surface (label printing surface). A concave groove for absorbing the convex shape of the stack rib of the dummy substrate at the time of bonding is provided on the bonding surface of the information substrate. Further, in Japanese Unexamined Patent Application Publication No. 10-222879, the "mold and manufacturing method of a bonded disk substrate" disclosed in Japanese Patent Application Laid-Open No. Hei 10-222879 has a structure in which a component for forming an inner peripheral portion on the substrate mirror side of an optical disk substrate forming die can be easily detached and replaced. By appropriately replacing these parts, the information substrate having the stack ribs on the mirror surface side and the dummy substrate having no stack ribs can be formed using the same mold. Further, in the "optical information medium" of JP-A-11-53770, the formation position of the stack rib protruding from the label printing surface of the dummy substrate is provided at a different radial position from the stack rib formed on the mirror surface side of the information substrate, When stacking the disks with both bonded together, avoid forming a gap between the disks with the width equal to the sum of the heights of both stack ribs, or do not provide the stack ribs on the dummy substrate, and conversely, on the label printing surface A channel ring of a concave groove is provided at a position corresponding to the stack rib of the information substrate, and when the optical disks after lamination are stacked, the convex portion of the stack rib and the concave portion of the channel ring are engaged with each other so that they are formed between the disks. The gap is reduced. However, in this method, when the dummy ribs are not formed with the protruding portions of the stack ribs but are temporarily stocked during the manufacturing process of the dummy substrate, the use of the spacer ring is difficult. Substrate loading / unloading operations are required, and the manufacturing equipment becomes complicated and expensive. In addition, if the dummy substrate is formed in a shape different from that of the information substrate, and the two are appropriately combined and bonded together, it is necessary to separately provide a dedicated manufacturing device for the dummy substrate and a dedicated information substrate, which increases the manufacturing equipment cost. I will.

A dummy substrate can be obtained by using the same molding die (manufacturing equipment) and rearranging some of the components as described in Japanese Patent Application Laid-Open No. Hei 10-222879, "Molding die and manufacturing method of bonded disc substrate". Even when both information boards can be manufactured, it is impossible to manufacture both at the same time.After manufacturing and storing a certain amount of one board, the necessary equipment is rearranged and the other is replaced. It is necessary to adopt a method of alternately repeating the manufacturing of the substrate, and it is not possible to avoid problems such as establishing an appropriate storage method of the optical disk substrate and securing a storage space.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to solve or avoid the above-mentioned problems in the prior art, and to provide a bonding method that can be used for both a dummy substrate and a information substrate in which a protrusion of a stack rib is not formed on a label printing surface. The structure of the optical disc substrate for use, the mold for molding, and the equipment for lamination make it possible to simultaneously mold the dummy substrate and the information substrate using the same molding equipment, thereby reducing the cost of manufacturing equipment and manufacturing optical discs. The layout of equipment is simplified and arranged, and the protection of the optical disk and the saving of the storage space at the time of the temporary storage in the single disk state in the optical disk manufacturing process and the stacked storage in the optical disk state after the lamination are compatible. To obtain an optical disk that does not hinder label printing on the optical disk Simultaneous molding of an optical disc substrate for lamination that can be used for both the dummy substrate and the information substrate using the equipment reduces the operational problems of the manufacturing equipment when manufacturing the information substrate and the dummy substrate alternately. The task is to avoid it.

[0013]

[Measures taken to solve the problem]

According to a first aspect of the present invention, in an optical disc substrate used for a laminated optical disc, a stack rib formed on an inner peripheral portion of a mirror side of the optical disc substrate has a cross section in the center axis direction of the disc. Instead of having the same rotationally symmetric body shape in the circumferential direction, it has an external gear-shaped convex shape that repeats a pattern combining projections of different shapes at a predetermined cycle, and also provides necessary information on the opposite information surface. The inner groove of the stamper, which is transferred to the optical disk substrate as pits or grooves, is fixed to the mold. This means that the stack ribs are formed in the same position with the same shape in which the unevenness is reversed.

[0014]

When the optical disc substrates are stacked, the top and bottom surfaces of the optical disc substrate are brought into close contact with each other or the phase is shifted by an appropriate amount so that the tooth portions of the stack ribs are aligned with the other optical disc substrates. It is possible to secure a gap of an appropriate size corresponding to the height of the stack rib between the optical disk substrates by overlapping the convex portion of the concave groove on the back surface of the optical disk.

[0015]

According to a second aspect of the present invention, based on the first aspect, a period of a repetitive pattern of a convex shape of a stack rib of the optical disk substrate and a concave groove shape by a claw portion of a stamper inner peripheral holder is provided. This cycle (pitch angle) is set to a central angle of 10 ° to 20 °.

[0016]

When the above optical disk substrates are stacked, the phase of the convex shape and the concave groove shape are shifted by an appropriate amount so that an operation variation in an operation of securing an appropriate size gap between the substrates can be absorbed, and the cavity is filled. It is possible to avoid occurrence of optical defects of the optical disk due to adversely affecting the flow state of the molten resin to be performed.

[0017]

A third aspect of the present invention is based on the first or second aspect of the present invention, wherein the convex shape of the stack rib of the optical disk substrate and the concave shape of the inner peripheral holder claw portion of the stamper are provided. Of the different shapes in one cycle of the repetition pattern, the ratio of the area of the disk center axis cross section of the smallest part to the part where the area of the disk center axis cross section of the protrusion or recess in one cycle is maximum is 2/3 to
3/4.

[0018]

According to the present invention, it is possible to avoid the occurrence of optical defects of the optical disk due to the adverse influence of the flow state of the molten resin filled in the cavity due to the presence of different irregularities in the circumferential direction.

[0019]

According to a fourth aspect of the present invention, there is provided an optical disk substrate molding die for forming an optical disk substrate according to the first to third aspects, wherein the stamper is formed by using a stamper inner peripheral press. When mounted on the gear, the pattern of the combination of projections of different shapes is repeated at a predetermined cycle The gear-shaped stamper inner circumference holding claw is repeatedly formed with concave grooves that are carved to form stack ribs on the opposite mirror surface The structure is such that it can be mounted by being shifted by a predetermined center angle with respect to the phase of the pattern shape.

[0020]

Function: When stacking and stocking optical disc substrates that have been molded, taken out of the mold, and have undergone the same delivery process, a proper gap is secured between the substrates without specially adjusting the position of the substrates. It is possible to stack and store optical disk substrates.

[0021]

According to a fifth aspect of the present invention, in the laminating method according to any one of the first to third aspects, the shape of the convex portion of the stack rib of the optical disk substrate and the inner peripheral holder of the stamper are provided. The bonding is performed by engaging the shape of the concave groove portion formed by the claw portion.

[0022]

According to the present invention, no projections are formed on the label printing surface, so that the screen for screen printing can be prevented from being damaged, and the storage space for stacking and storing optical disks after lamination can be prevented from becoming excessive. .

[0023]

According to a sixth aspect of the present invention, in the laminating apparatus for laminating optical disk substrates according to the first to third aspects, the convex shape of the stack ribs of the optical disk substrates to be bonded to each other and the inside of the stamper are provided. A mechanism for reading the repetitive pattern of the concave groove shape by the peripheral holder claw portion, and matching the read phase of the convex portion and the phase of the concave portion,
A feature is provided that a mechanism is provided for engaging and sticking the irregularities of both.

[0024]

The phase adjustment in the rotation direction between the convex shape of the stack ribs of the optical disk substrates to be bonded to each other and the concave groove shape by the claw portion of the stamper inner peripheral holder can be automatically performed, and the bonding can be performed efficiently. It is possible to efficiently manufacture an optical disk having no protrusion on the label printing surface.

[0025]

A seventh aspect of the present invention is to provide an optical disc by using the optical disk substrates of the first to third aspects and bonding them by the bonding method of the fifth aspect.

[0026]

According to the present invention, it is possible to avoid damage to the screen on which screen printing is performed, and to obtain an optical disk which does not require an excessive storage space when stacked and stored.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an optical disk substrate, an optical disk substrate molding die, an optical disk substrate bonding apparatus, and an optical disk according to the present invention will be described with reference to the drawings. An optical disc substrate 81 according to the present invention has an annular convex portion of a stack rib 61 formed on an inner peripheral portion excluding a mirror-side information recording area and a clamp area area, similarly to a normal information board optical disc substrate. A pit or a guide groove engraved on the stamper is transcribed on the information recording surface on the opposite side, and the inner hole of the stamper 71 is mechanically held on the inner periphery and fixed to a mold. Pressing the inner circumference of the stamper (see stamper press 72 in FIG. 8)
Are formed as concave grooves 83. The convex shape of the stack rib 61 is basically a ring shape along the disk center rotation axis as shown in FIG.
The cross-sectional shape is generally a trapezoid (or a triangle, an ellipse, or the like) and is generally a rotationally symmetric body having a uniform shape in the circumferential direction. The embodiment of the present invention shown in FIG. The stack rib 61 has a pattern formed by combining trapezoids having different cross-sectional shapes with a certain period α (one pitch angle).
It is shaped like an external gear. In the case of an external gear, for example, the radial cross-sectional shape of the tooth portion 62 is a trapezoidal shape as shown in FIG. 6B, and the radial cross-sectional shape of the tooth bottom is as shown in FIG. It has a trapezoidal shape with shorter top and bottom sides than. These teeth 62,
The cross-sectional shape of the tooth bottom portion 63 is not necessarily a trapezoid, but the inner and outer surfaces in the radial direction are sloped in consideration of the convenience in molding with a mold.

Also, as shown in FIG. 8, the claw shape of the stamper inner periphery holding member has a trapezoidal (or triangular, elliptical, etc.) cross-section along the disk center rotation axis and a uniform shape in the circumferential direction. In general, in the embodiment shown in FIG. 6 of the present invention, the outer peripheral gear has the same external gear shape as the stack rib, and the radius at which the claw is formed. The position is the same radial position as the radial position where the stack rib is formed. as a result,
As shown in FIG. 6D, a concave groove 65 having the same planar shape as the convex shape of the stack rib formed on the mirror surface is formed on the information surface side of the optical disk substrate formed by the present invention. It is formed at a radial position. The concave portion 66 of the concave groove 65 illustrated in FIG. 6D corresponds to the tooth portion 62 in FIG. 6A, and the convex portion 67 corresponds to the tooth bottom portion 63, and has substantially the same shape. An optical disc substrate 81 having concave and convex grooves 65 formed on the front and back sides by the external gear-shaped stack ribs 61 and claws for pressing the inner periphery of the stamper (see FIG. 9).
When the gears are successively stacked, as shown in FIG. 7, when the gears are phase-matched so that the tooth portions 62 of the stack ribs 61 and the concave portions 66 of the concave grooves 65 coincide with each other, The toothed portions 62 of the stack ribs 61 fit into the concave portions 66 of the concave grooves 65, and as a result, the overlaid optical disk substrates overlap with each other in a close contact state (see FIG. 9). Also, when the phases are shifted appropriately (for example, by a half pitch angle) and overlapped, the tooth portions 62 of the stack ribs 61 overlap the convex portions 67 of the concave grooves 65, and the stacks are stacked between the optical disk substrates that are overlapped. Rib 6
Both are placed one on top of the other with an air gap 91 only interposed therebetween (a height corresponding to the height) (see FIG. 10).

As described above, the optical disc substrate 81 having the form according to the present invention can be formed by adjusting or shifting the phases of the above-described tooth profiles of the upper and lower optical disc substrates 81 when they are superposed. 81, 81 can be closely attached to each other, or a predetermined gap 91 can be interposed between the substrates. Utilizing such features, a reflective film and a protective film on the information surface side, and in the case of an optical disk that is not read-only but rewritable, an information substrate on which a necessary film such as a recording film is further formed,
Further, if an adhesive layer such as a UV adhesive is applied and a dummy substrate having the same form as the information substrate is superimposed and adhered as shown in FIG. 9, projections that damage the screen for screen printing on the label printing surface are formed. A laminated optical disk in which is not formed is obtained.

In the optical disk substrate bonding apparatus according to the present invention, a detecting means for reading the shape (phase in the rotation direction) of the stack rib 61 on the optical disk substrate surface and the concave groove 65 on the rear surface by an optical method such as a CCD; There is a phase adjustment mechanism that overlaps the optical disk substrates so that they fit together (see FIGS. 7 and 9). Then, the optical disk obtained in this manner and the optical disk substrate in each step before bonding are combined with the tooth portion (convex portion) 62 of the external gear-shaped stack rib 61 and the concave groove 65 on the back surface as shown in FIG. By disposing the concave portions 66 in a rotational direction and stacking them, the stacked disks can be appropriately stacked and stored while avoiding direct contact between the front and back surfaces of the stacked disks to cause optical defects. is there.

The above-described phase adjustment mechanism optically reads the stack rib 61 and the concave groove on the back surface of the conventional optical disk transport handling device, processes the image, and measures the phase shift amount of these irregularities. However, any structure may be used as long as the rotating optical device rotates the picked-up optical disk substrate by an angle necessary to shift or match the phase by a predetermined amount. An outline of an example of the transfer handling device will be described with reference to FIG. The feature of this apparatus resides in an arm head 111 provided at the tip of the transfer arm 110. In addition to the suction mechanism for vacuum-sucking the optical disk substrate to the arm head 111, a stack rib 61 (not shown) of the optical disk substrate and a rotation motor (pulse motor) 112 for rotational driving are incorporated. Note that an imaging device that captures the annular groove 65 on the back surface of the optical disk substrate that is attracted to the arm head 111 is separately provided near the bonding stage 114 (not shown). Images from these imaging devices are sent to an appropriate image processing device (not shown), and the phases of the tooth portions 62 and the tooth bottom portions 63 of the stack ribs 61 on the optical disk substrate and the annular grooves 65 are provided.
The phase of the concave portion 66 and the convex portion 67 is recognized. Then, based on the two phase information, a signal is sent to the turning motor 112, and the optical disk substrate sucked by the arm head 111 is rotated by a required angle. The optical disk substrate loaded on the substrate supply stage 113 is loaded with necessary processing (for example, formation of a recording film).

The specific operation is as follows. First,
The first substrate is transferred to the bonding stage 114. At this time, the stack ribs 61 (see FIG. 6) on the optical disk substrate are taken into the image processing apparatus, and the phase of the stack ribs 61 that is the reference of the bonding stage 114 is determined. Next, an adhesive is applied to this. Subsequently, the second substrate is transferred to the bonding stage 114, and the following operation is performed during this process. First, one second substrate is adsorbed to the arm head 111 from the substrate supply stage 113 for transfer. At this time, the imaging device captures the annular groove 65 on the back surface of the second substrate, and the phase of the annular groove 65 on the back surface of the second substrate and the stack rib 61 of the first substrate on the bonding stage 64 in the image processing device. Is calculated. Next, based on the calculated phase relationship between the two, the tooth portion 62 and the tooth bottom portion 63 of the stack rib 61 of the first substrate and the concave portion 66 and the convex portion 67 of the annular concave groove 65 of the second substrate are accurately overlapped. The rotation motor 112 of the arm head 111 is rotated (that is, so that the two substrates come into surface contact), and after a predetermined rotation operation, the second substrate is lowered onto the bonding stage 114 and the first substrate Place on top. The first and second substrates stacked on the substrate supply stage 113 with an air gap therebetween are adhered and adhered in a state of surface contact on the lamination stage 114 by the above series of operations. . The optical disk on the bonding stage 114 is attracted to the arm head 111 and transferred to the bonding media storage stage 115.

Since the above operation control is integrally performed by the processing unit of the image processing apparatus, the rotation phase adjustment and the laminating operation of the optical disk substrate by the turning motor 112 are performed under completely automatic control. Also, when the optical disks after lamination are stored in a stacked state, the protrusion of the stack rib 61 is formed only on one surface, so that no extra space is required during the stacked storage.

Further, the optical disk according to the present invention has a configuration in which an information substrate and a dummy substrate having the same form are bonded as described above. This means that the information substrate and the dummy substrate can be molded using the same molding equipment, and the optical disk substrates molded by a certain molding equipment are stacked and stored for every single sheet or every predetermined number of sheets. Each of the lots can be sorted for an information substrate or a dummy substrate and put into a subsequent process. for that reason,
There is no need to install separate molding equipment for forming the information substrate and for forming the dummy substrate, and therefore the equipment cost can be reduced. Also, in order to form information boards and dummy boards of different forms, after manufacturing and storing one board in a certain quantity, the necessary equipment is rearranged and manufacturing of the other board is alternately repeated. The additional problem of having to secure a storage space and establish a storage method caused by adopting the method is avoided.

In the mold for molding an optical disk substrate according to the embodiment of the present invention, a stamper inner peripheral holding member 72 for mechanically holding an inner peripheral portion of the stamper and setting the stamper in the die is mounted on the die. In doing so, with respect to the phase of the gear-shaped concave groove 74 of the mold for forming the stack rib,
The pawl 73 of the stamper inner peripheral holding member 72 in the form of an external gear is positioned so as to be shifted by a predetermined angle. Therefore, the shape of the protruding external gear of the stack rib 71 of the optical disk substrate to be formed is a predetermined center angle (for example, 1) with the gear shape of the concave groove 65 on the opposite surface (back surface).
(/ 2 pitch). Therefore, when stacking and storing optical disk substrates that have undergone the same transfer operation, including the operation of removing the molded optical disk substrate from the mold to the outside of the mold, perform special alignment between the upper and lower substrates when stacking. Even if not provided, a predetermined gap can be interposed between the substrates as shown in FIG. In the present invention, the optical disk substrate 81
The period (pitch angle) of the repetitive pattern α of the convex shape of the stack rib 61 (see FIG. 9) and the shape of the concave groove 65 formed by the stamper inner peripheral holder claw portion is set to a central angle of 10 ° to 20 °. At the same time, for the differently shaped portions in one cycle of the repetitive pattern, the ratio of the area of the disk center axis cross section of the minimum portion to the portion where the cross section area of the disk center axis of the protrusion or recess in one period is the maximum is 2/3 to 3/4. The shape is set so that By setting as described above, the presence of different irregularities in the circumferential direction adversely affects the flow state of the molten resin filled in the cavity, thereby causing an optical defect on the optical disk substrate. In addition, it is possible to absorb variations in operations in each delivery operation from a substrate removal operation after the optical disk substrate is formed to a substrate stacking storage operation after the optical disk substrate is formed.

[0036]

The effects of the present invention are summarized below for each of the claimed inventions. 1. In the optical disc substrate used for the bonding type optical disc, the stack rib formed on the mirror surface side inner peripheral portion of the optical disc substrate has the same rotationally symmetrical body shape in the circumferential direction in the cross section of the disc center axis. Rather, it has an external gear-shaped convex shape in which a pattern combining protrusions of different shapes is repeated at a predetermined cycle, and the optical disk substrate is formed by a claw of a stamper inner peripheral holding member that fixes an inner peripheral portion of the stamper to a mold. The concave groove formed in the inner peripheral portion of the information surface side is formed in the same radial position as the stack rib in the same concave groove shape with the concave and convex reversed from the stack rib, so that when stacking optical disc substrates, The substrates can be brought into close contact with each other by adjusting the phase of the irregularities described above, or by shifting the substrate by an appropriate amount after the rotation, so that the substrates have an appropriate size. Space can be secured.

2. According to the second aspect of the present invention, the cycle of the convex pattern of the stack rib of the optical disc substrate and the cycle of the repetitive pattern of the concave groove formed by the stamper inner peripheral holder claw portion have a central angle of 10 ° to 20 °.
°, so that when the optical disc substrates are stacked, the phases of the convex and concave shapes are shifted by an appropriate amount to absorb the variation in the operation of securing the appropriate size space between the substrates. In addition, the flow state of the molten resin filled in the cavity is not adversely affected, and therefore, it is possible to avoid the occurrence of optical failure due to the adverse effect.

3. According to the third aspect of the present invention, the shape of the stack rib of the optical disc substrate according to the first or second aspect and the shape of the concave groove formed by the stamper inner peripheral holder claw portion which are different in one cycle are different in one cycle. In this case, the ratio of the area of the disk center axis cross section of the minimum portion to the portion where the area of the disk center axis cross section of the convex portion or the concave portion becomes maximum is 2/3 to 3/4.
Due to the presence of different irregularities in the circumferential direction, the flow state of the molten resin filled into the cavity is adversely affected,
For this reason, occurrence of an optical defect is avoided.

4. According to the fourth aspect of the present invention, in the optical disk substrate molding die for molding the optical disk substrate according to any one of the first to third aspects, when the stamper is mounted on the die by using the stamper inner peripheral pressing, a projection having a different shape is formed. A repetitive pattern of concave grooves engraved to form a stack rib on the mirror surface (cavity surface) of the mold opposite to the external gear tooth-shaped stamper inner circumference holding claw that repeats the combined pattern at a predetermined cycle With a structure that can be mounted by being shifted by a predetermined angle with respect to the phase of the optical disc substrate, it is taken out after the molding process, and when stacking and stocking optical disc substrates that have undergone the same delivery process, special It is possible to stack and store optical disc substrates with appropriate gaps between the optical disc substrates without adjusting the position. It becomes possible.

5. According to a fifth aspect of the present invention, in the laminating method for laminating an optical disk substrate according to any one of the first to third aspects, the shape of the convex portion of the stack rib of the optical disk substrate is matched with the shape of the concave groove formed by the claw portion of the stamper inner peripheral holder. Since the alignment is performed, it is possible to avoid damaging the screen for screen printing without forming projections on the label printing surface, and to avoid excessive storage space when stacking and storing optical disks after lamination. can do.

6. In the laminating apparatus for laminating the optical disk substrates according to the first to third aspects, the convex shape of the stack ribs of the optical disk substrates to be laminated to each other and the concave groove shape by the claw portion of the stamper inner peripheral holder are repeated. By providing a mechanism for reading the pattern and a mechanism for matching the phases of the read convex portions and concave portions, and engaging and bonding the two concave and convex portions, an optical disc having no projection formed on the target label printing surface is obtained. be able to.

7. About the invention according to claim 7 The optical disk substrate according to claim 1 to claim 3 is bonded by the bonding method according to claim 5,
The screen can be prevented from being damaged when screen printing is performed on the obtained optical disc, and the storage space in stacking storage can be prevented from being excessive.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a related art in a state where optical disk substrates having no stack ribs are stacked.

FIG. 2 is a perspective view of a conventional optical disk substrate.

FIG. 3 is a cross-sectional view of another conventional technique in which optical disc substrates having stack ribs on the upper surface are stacked.

FIG. 4 is a cross-sectional view of a conventional optical disk on which an optical disk substrate having an upper surface is bonded.

FIG. 5 is a sectional view of still another conventional technique in which optical disc substrates provided with stack ribs on both front and back surfaces are stacked.

6A is an enlarged perspective view of a part of the stack rib according to the embodiment of the present invention, FIG. 6B is a radial cross-sectional view of the tooth portion 62 of the stack rib of FIG. (c) is a radial cross-sectional view of the tooth bottom of the stack rib of (a), and (d) is a plan view of a part of the stack rib of (a).

FIG. 7 is an enlarged perspective view of a part of the annular groove of the embodiment formed on the back surface of the optical disk substrate by the stamper holding claw.

FIG. 8 is a schematic sectional view of a conventional cavity for molding an optical disk substrate.

FIG. 9 is a partial cross-sectional view of an optical disk in which an optical disk substrate according to an embodiment of the present invention is attached and bonded.

FIG. 10 is a partial cross-sectional view showing a state where optical disc substrates according to the embodiment of the present invention are stacked.

FIG. 11 is a plan view schematically showing an outline of an example of a transfer handling device.

[Description of Main Codes] 61: Stack rib 62: Tooth portion 63: Tooth bottom portion 65: Annular concave groove 66: Depressed portion 67: Convex portion 71: Stamper 72: Stamper inner periphery pressing 73: Stamper inner periphery pressing claw 81: Optical disk substrate 91: Gap 110: Transfer arm 111: Arm head 112: Rotating motor 113: Substrate supply stage 114: Lamination stage 115: Lamination media storage stage

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // B29L 17:00 B29L 17:00

Claims (7)

[Claims] 1. An optical disk substrate used for a laminated optical disk, wherein a stack rib formed on an inner peripheral portion of the optical disk substrate on the mirror surface side is not a rotationally symmetric body shape which is the same in the circumferential direction in the cross section of the disk center axis. A stamper that has an external gear-shaped convex shape in which a pattern combining projections of different shapes is repeated at a predetermined cycle, and that transfers necessary information on the opposite information surface as pits or grooves onto the optical disc substrate. The concave groove formed on the information surface side inner peripheral portion of the optical disk substrate by the claw of the stamper inner peripheral holder for fixing the inner peripheral portion to the mold is located at the same radial position as the stack rib, with the same irregularities as the stack rib. An optical disc substrate characterized by being formed in a concave groove shape. 2. The optical disk according to claim 1, wherein the cycle of the repetitive pattern of the convex shape of the stack rib of the optical disk substrate and the concave shape formed by the inner peripheral holder claw portion has a central angle of 10 ° to 20 °. substrate. 3. A different shape portion in one cycle of a repetitive pattern of a convex shape of a stack rib of the optical disc substrate and a concave groove shape by a stamper inner peripheral holder claw portion.
2. The ratio of the area of the disk center axis cross section of the minimum portion to the portion of the projection or recess having the maximum disk center axis cross section in one cycle being 2/3 to 3/4. 2 optical disk substrate. 4. A mold for molding an optical disk substrate for molding an optical disk substrate according to claim 1, wherein projections having different shapes are combined when the stamper is mounted on the die by using a stamper inner peripheral press. A predetermined center angle with respect to the phase of the repetitive pattern shape of the concave groove formed to form the stack rib on the opposing mirror surface with the external gear shaped stamper inner peripheral holding claw that repeats the pattern at a predetermined cycle. An optical disk substrate molding die having a structure capable of being mounted by being shifted only by being shifted. 5. The bonding method for bonding optical disk substrates according to claim 1, wherein the shape of the convex portion of the stack rib of the optical disk substrate and the shape of the concave groove formed by the claw portion of the stamper inner peripheral holder are bonded. An optical disc substrate bonding method characterized by performing the following. 6. A laminating apparatus for laminating optical disk substrates according to claim 1, wherein a repetitive pattern of a convex shape of a stack rib of the optical disk substrates to be laminated to each other and a concave groove shape by a claw portion of a stamper inner peripheral holder is read. An optical disc substrate bonding apparatus, comprising: a mechanism, a mechanism for matching a phase of a convex portion and a phase of a concave portion read out, and engaging and bonding the two concave and convex portions. 7. An optical disk having a structure bonded by the bonding method according to claim 5, using the optical disk substrate according to claim 1.